As the environmental awareness gains popularity, green energy is believed to be the future energy for mankind. Because green energy is being valued, people have been putting a greater effort into the development of solar power, hydroelectric and wind power. Nevertheless, regardless of the efficiency of the power generation, solar power and wind power are easily affected by the environment and the weather. For example, when there is low sunlight exposure or no sunlight, solar power is unable to convert solar energy into electricity effectively, and as for wind power, it cannot be generated when the current weather is windless. Therefore, it is required to develop a power generation system which utilizes natural power and can work 24 hours a day regardless of the limitations of the environment and the weather.
Since waves are always along the coastlines, wave energy is getting more attention from researchers and developers, because wave energy is renewable and utilizing wave energy does not harm the environment.
A wave power generation device usually includes a floating body, a hydraulic assembly and a power generation assembly. The floating body is disposed on the hydraulic assembly, while the hydraulic assembly connects to the power generation assembly. The floating body is configured for moving up and down with the fluctuations of the waves, thereby driving the hydraulic assembly to work for generating electricity by the power generation assembly. In detail, the hydraulic assembly includes a hydraulic cylinder and a piston. As the floating body moves up and down, the hydraulic cylinder is driven to move relative to the piston. As a result, the oil in the hydraulic cylinder is pushed to the power generation assembly, so as to make the power generation assembly convert mechanical energy from the waves into electricity.
However, air gets compressed, and when unexpected air remains in the hydraulic cylinder, it is repeatedly compressed during the compression process of the hydraulic assembly, which reduces the efficiency of power generation because the oil cannot be pushed to the power generation assembly by the piston smoothly. Consequently, in order to improve the power generation efficiency of the wave power generation device, it is crucial to find a solution for the remaining air in the hydraulic cylinder.